Currently, bubble paper or PVC is mostly used to cover an article upon packing of the article, but the cushioning effect is not good, and environmental pollution is a byproduct. To solve the defects of bubble paper and PVC, an air packing bag is developed, which is heat-sealed to form airtight air cylinders, and configured with air filling entrances allowing air filling; the air packing bag can be used as a cushioning material in interior packaging after air is filled in the air cylinders through the air filling entrances.
However, bending areas at the bottom of a general package bag usually cannot present a flat shape; an outward protuberance is always naturally generated due to compression of air pressure after the package bag is filled with air and expanded, such that the package bag cannot be placed on a level surface stably.